How to write an invoice

An invoice is a request for payment that also has to survive being filed, queried and audited. Everything on it is there because somebody downstream needs it: your client's accounts payable, your own bookkeeping, or a tax authority years later.

What every invoice needs

  • The word "Invoice", so it is not filed as a quote
  • A unique invoice number
  • The date you issued it, and the date payment is due
  • Your business name, address and contact details
  • Your client's business name and address
  • A line for each item of work, with quantity, unit price and total
  • Any tax, shown separately from the amounts it applies to
  • The total amount due, in the currency you expect to be paid in
  • How to pay you, and what happens if payment is late

Writing one, start to finish

  1. Number it before you write anything else

    A unique number is what lets you and your client refer to this document later. Sequential is fine; gaps are not a problem, but duplicates are.

  2. Date it, and set the due date explicitly

    "Net 30" means thirty days from the invoice date, and half your clients will read it as thirty days from when it reaches them. Print the date itself and the argument disappears.

  3. Describe the work the way the person paying will recognise it

    The person approving the invoice is often not the person who hired you. "Consulting" gets queried; "Website redesign, phase 2, February" gets approved.

  4. Show tax on its own line

    A total with tax folded into it cannot be checked, and an invoice that cannot be checked waits on somebody's desk.

  5. Say how to pay and what happens if payment is late

    A late fee you did not state is a late fee you will not collect.

Sending it

Send it the day the work is finished, as a PDF, to a person rather than to an inbox nobody owns. An invoice that arrives three weeks late has already taught your client that the date on it is negotiable.

You can fill one in and download the PDF with the free invoice generator — no account, no watermark.

Make an invoice now

Common questions

Does an invoice have to be numbered?
In practice, yes. The number is how the document is referred to in a payment reference, a query and an audit, and duplicate numbers are what make a set of records impossible to reconcile.
What is the difference between an invoice and a receipt?
An invoice asks for money. A receipt confirms money has been received. The same job usually produces both, in that order.
How soon should I send an invoice?
The day the work is finished. Payment terms start from the invoice date, so every day you wait is a day added to when you are paid.

Related guides